SEAT GP-HEATED 1012354 - Caterpillar

Illustration 1 g00813477
The load pressure oil from the implement with the highest load pressure regulates the flow to the other implements through all flow compensators.When one hydraulic circuit is activated, pump standby pressure oil is directed to the bottom of the flow compensators. The compensator valve moves up. When the valve moves up, the center passage in the compensator opens the cross-drilled passage to the load sensing port. The pump output pressure oil then goes to the load sensing spool in the main pump regulator. The pressure increase in the load sensing valve causes the pump system pressure to increase. When the pump output pressure increases to more than the implement load pressure, the load check valve opens. The opening in the load check valve allows flow across the activated control spool and under the flow compensator valve to the implement.The load sensing pressure oil also flows around the compensator valve to the spring chamber at the top of the compensator valve. The load pressure oil and the spring force push down on the compensator valve. Pump flow to the implement is metered along the bottom of the flow compensator valve.When more than one implement is activated, the highest load pressure oil is directed through internal passages to the spring chamber at the top of all flow compensator valves. The load sensing pressure oil from the circuit with the most load pressure determines the flow rate through each compensator valve.Illustration 1 displays compensator valves. The view at the right is a flow compensator valve in the circuit with the highest circuit pressure. Pump output flow moves the compensator valve upward. The pressure oil goes through the passages to the load sensing signal line to the pump regulator. The pump upstrokes in order to increase flow. The load sensing pressure oil also goes to the spring chamber at the top of the compensator valve. The pressure oil pushes the compensator valve downward and the pump flow is metered past the bottom of the compensator valve to the implement.The valve that is displayed in the center is a flow compensator valve from a circuit with low work load pressure. The high load sensing pressure oil is directed to the top of the flow compensator valve. When the implement control valve is moved, pump output pressure oil moves the compensator valve upward. The compensator valve moves until the passage to the implement is open. Pump flow is metered along the bottom of the valve to the implement with the lower pressure. The compensator valve does not move upward enough to open the load sensing signal line.The valve that is displayed at the left is a flow compensator valve in the neutral position. The load pressure from the implement with the most pressure keeps the compensator valve closed.